1. Field of Invention
The present invention relates to the field of a headphone, and more particularly to a jack for preventing the headphone from inputting double audio sources.
2. Description of Related Arts
FIG. 1 is a sketch view of a conventional headphone jack which has a pair of audio jacks provided thereon. The pair of audio jacks comprises a left audio jack 1 and a right audio jack 2, which are respectively provided on a left earpiece 6 and a right earpiece 7. Both the left audio jack 1 and the right audio jack 2 comprise: a common grounding contact 3 for contacting a core terminal of an audio connector; a left earpiece conductive terminal 4 for contacting an external ring terminal of the audio connector and connecting the left earpiece; and a right earpiece conductive terminal 5 for contacting a middle ring terminal of the audio connector and connecting the right earpiece. When one audio connector is plugged into the left audio jack 1 or the right audio jack 2, inputted audio signals pass through the left earpiece conductive terminal 4 and the right earpiece conductive terminal 5 and then are transmitted to the left earpiece and the right earpiece, in such a manner that the headphone is capable of being utilized normally for playing audio; when two audio connectors are simultaneously plugged into the left audio jack 1 and the right audio jack 2, two inputted audio signals simultaneously pass through the left earpiece conductive terminal 4 and the right earpiece conductive terminal 5, and then are simultaneously transmitted to the left earpiece and the right earpiece, in such a manner that the headphone is capable of being utilized normally to play audio.
The conventional stereo headphone has more than two built-in audio jacks which are respectively provided on the left earpiece and the right earpiece. By plugging the audio connector into the audio jack, users are capable of accomplishing transmitting audio signals inputted by audio sources, such as a music player or a mobile phone, to the stereo headphone to play audio. There are two characteristics in providing two audio jacks. Firstly, users are capable of making a choice to input and selecting any desired one of the two audio jacks. Secondly, users are capable of connecting the audio jack with the audio jack of other stereo headphone, in such a manner that sharing music is achieved. Although the characteristics mentioned above are apparent, this type of structure leads to some disadvantages as follows.
1) A parallel configuration of the two audio jacks will affect the overall impedance of the headphone under a sharing mode and reduce the quality of the music while sharing the music.
2) The music player or the audio source requires a high output to maintain an identical sound power, which leads to distortion and affects the service life of the battery.
3) The problem of mutual interferences between the left channel and the right channel of the headphone will affect other headphones via connection.